The present invention is directed towards a method for controlling comparisons to be carried out between reference data elements and input data elements proceeding from a source file.
More precisely the present invention is directed towards a method and apparatus of the type according to which reference data elements of the same type are drawn up in respective columns of a reference table and compared in parallel to input data elements proceeding from a file. A method of this type is disclosed in U.S. Pat. No. 4,053,871, the disclosure of which is incorporated herein by reference. In this method, each input data element proceeding from a file (e.g. a name) comprises one or more individual items of information (e.g. the letters of the name) which are received sequentially and are compared in parallel and in succession with the individual items of information (e.g. letters) of the same rank of the reference data elements (e.g. names) contained in the successive lines of the table. The successive results of these matchings are combined in order to provide the result of the comparison and to decide upon the information which is to be stored.
Processing of the input data from a file necessitates marking of the data. When the latter has a complicated construction, marking by means external to the file is difficult and laborious, especially if the file is of large capacity and is subject to frequent updatings.
External marks may be dispensed with by introducing into the file localization elements such as special data elements or labels and special characters or separators such as described in U.S. Pat. No. 4,053,871. Different comparison sub-assemblies may be employed for marking the separators, labels and data with a view to localizing in the file the items of information which are to be recognized and if necessary to be stored.
However, when the construction of the information contained in the file is complicated one must have recourse to a high number of labels and separators, which complicates the system of processing of the file.
In addition to the foregoing, the present invention has the aim of providing a method of microcontrol which enables the method of comparison described above to be applied to items of information being received from a file having any construction (i.e., of any format) while working at the frequency at which the items of information delivered by the file, without external marking and while controlling the simultaneous execution of the elementary functions connected with both the comparison and with the storage operations to be carried out, without interruption of the evolution of the file. These elementary functions (which are to be executed simultaneously) relate to the localization, to the processing and to the transfer of the items of information proceeding from the file, to the sequential linkages of the groups of simultaneous operations and to the tests concerning the results obtained from the preceding comparisons. The items of information subjected to the method of comparison may be of fixed or variable length, the method of control then enabling in particular, a reduction in the number of labels and separators necessary to the localization of the data which are to be worked. The processes which are to be executed may, depending upon the method of control, allow of any of the forms of looping which the processing of a construction of items of information may call for.